John blake tare



PATENT'ED JULY 7, 1868.

A J. B. TAR-R.l

CAST IRON GAR WHEEL.

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Letters .Patent No. 79,611, dated July 7, 1868.

IMPROVEMENT IN GAST-IRON GAB-WHEELS.

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TO ALL WHOM IT MAY CONCERN:

Be itkno'wn that I, JOHN BLAKE TABR, of Fair Haven, in the county of Bristol, and State of Massachusetts, have invented an Improved Cast-Iron Car-Wheel; and I do hereby declarethat the following is a full, clear, and exact description thereof, reference being' had tothe accompanying drawings, making a part ofthis sp.eciiica tion, in which- Figure 1 is a front elevation of a machine which is adapted for the production of my improved wheels.

Figure 2 is a section through the machine, taken in the horizontal plane indicated by 'red line x a: iu iig. 1.

Figure 3 is a vertical central section, taken through the lower par-t of the machine, showing a wheel within the mould.

Figures 4 and tiaepresent one 4form of car-wheel, as produced by my improved method and machine,

. Similar letters of reference indicate corresponding parts in the several iigures.

This invention relates to a' new and improved processof treating cast iron in the manufacturev of railroadcarw heels, whereby wheels made of this material will bemuch stronger, cheaper, less liable to aws and other imperfections, and better in every other respect than cast-iron wheels made by any other known process.

Owing to the difficulties hitherto attending the production of car-wheels of cast iron, and the uncertainty of producing wheels of this material without flaws, railroad-engineers have, in many instances, substituted steel wheels instead of cast-iron wheels. But steel wheels are very expensive, costing from seventy-five to one hundred and iifty dollars, and their production is attended with many diiculties which uro not experienced with cast iron,

The nature of my invention consists in ell'ecting the compression and' condensation of cast iron during the act of giving to it the form of a car-wheel, and, while this metal is iu a liquid or plastic condition, keeping the metal under considerable pressure until it has set suiciently to retain the shapeand density imparted to it, as will be hereinafter described.

The following desciption will enable others skilled in the art to understand and carry into eect my improved process of making car-wheels of cast iron.

In conducting -the improved proces-s it is necessary to employ metal moulds, or moulds of some material possessing suihcient strength to withstand the pressure-which is applied to the metal while in a plastic state; also, to employ certain means whereby sir or gases will be allowed to escape from the metal while under pressure in the mould; also to provide for -applying powerful pressure Vto the' metal 'while it is couiued within a mould, and to keep it under such pressure, while cooling,un`til it has set; end iinally, it is necessary .to provide for releasing the car-wheels from restraint at a proper time, to prevent them from shrinking unevenly.

The mould within which the wheels are produced is composed of three sections, B, C, and D, vwhich may wholly or partially be lined with some suitable refractory substance, to prevent a rapid destruction ofthe inetal of which these sections are composed. These threesectious should also be made strong enough to sustain considerable pressure without yielding in the slightest degree.

The section D is a circular plate,'with a hole made vertically through 'its centre, and with a circular concavity formed in its upper surface, of a shape corresponding to the shape of the inside face'of a car-Wheel, and a portion of the flange thereof. This section D, when in place, fits snugly into an annular recess, s, made coucentrcally in the upper surface of a base-plate or ring, A, as shown in figs. 2 and 3. The section B is a strong ring of metal, which is designed to produce the tread or periphery of a car-wheel, and also a portion of -the flange thereof, and which is made so as to fit snugly withinthe recess s, in base-plate A, and ou top of the bottom section D of the mould. i I The top section KC of the mould, l shall denominate a pressing-head, for it is through the medium of this section that the metal in the mould is pressed. This head is shaped on its bottom surface so ns to produce the outcrface of a car-wheel, and thc rim thereof, as shown in iig. 8, and it is adapted to-iit withinthe ring-.section but not to tit so tightly therein as to prevent thc escapo of air or gas between itand. the ring..

The sprue er pouring-hole o'r holes't are made vertically through the pressing-bend C, and provided on top of this head ivith cut-oil` slides it, which are dove-tailed and tted -to work between guides z z', shown in iigs. 1,' 2, and'; The slide h is designed for cutting oi the superiluity of metal left over the sprue-hole t, after filling the mould, and also for closing the sprue-hole so that the' metal will. not be forced ont throughvthis holo when pressure is applied to the pressing-headl The pressing-head C has a vertical' hole made through its centre, the axisof which coincides with the axis of the hole which is made through the centre of the bottom section D, of

the mould. The hubs of the wheels are produced by mskihgeorresponding recesses inthe top and bottom sections G, D, as shown in iig` 3.

Three vertical rods, d, d d, nrc 'occured to they pressing-head C,'u.nd Varranged concentricnlly around the' centre o f this head at equal distances apart. These rods are carried up throughs. guide-plate, c, and through n head-plate,'H, and are connected to a piston working in n cylinder, I. By the ascent and descent ofthe piston in cylinder I, the h'ead C is caused to rise and descend.

Beneath the head-plate H is a small cylinder, G, the vertical axis of which coincides with the axis of the cylinder H, and the mould-sections Within cylinder G works a piston, to which n. rod,b, is secured, which.

rod extends downward, and has a core, a, which may be made slightly tapering, applied upon its lower portion b', ss shown in iig. 3. This core is designed tcleave holes through the centres ofthe car-wheels, and it may be lmede'oi a suitable refractory substance. and held in place on the lower portion b of piston-rod b, between a collar a-and a nut, al.

The core a is`made tapering, so that it may be readily withdrawn from the casting when the latter hw' properly set.

The heed-plate E is supported upon. andh-eld down by means of pillars A', as shown in the drawings,

which should be of sudcient strength to resist the upward strain against the heachplate H during the act of pressing and condensing the metal in the mould.

Each one ofV the cylinders shonldbe suitably connected by pipes -with force-pumps, which are made upon theprinciple of' the welldrnown forcepumps used for hydrostatic presses, so that the pistons in these cylinders can be forced upward and downward, at pleasure.

The operation is as follows Three mould-sections are brought together, as shown in iig.` 3, with the core a'in position to produce a hole through the wheel when cast. The mould is then lled with melted'cast iron, and the slide li moved over -the .sprue-hcle t; Pressure is then applied to the head C, and the metal in the mould thereby condensed. When tue wheel becomes cool enough to allow of its releasefrom the mould-sections, the core `a 'is first retracted, then the head C is raised, and iinally' the riug'B is lifted free from the wheel, leaving the wheelfto cool upon the bottom section lof the mould.

The hooks g g, which are represented in figs. 1 and 2, are designed for holding the ring-section B down in place until the pressing-head C is lifted free from the casting, when these hooks are turned to one side, and this ring allowed to be lifted by the'hooks which extend over thepressing-head. The hooks g g are designed to serve as gauges for determining the descent of the pressing-head, and regulating the density of the wheels castinthe mould.

Instead of employing 'hydrostatic pressure,` screw or ,lever-pressure may be adopted, but I prefer to' use hydrostatic power, because the machinery requiredin the application of this power isI more readily manipulated than any other with-which I om acquainted. v

By vsubjecting ca'stpiro'u to considerable pressure while it ,is in a molten or plastic condition, andwhile. it is conned within the mould whichiis to give to it-the iinal or desired shape, an extraordinary strength and closenessis imparted to this metal. The bres or grain et' the metal are reduced and compacted tov such a degree that s piece of the fractured metal presents morethe appearance of ine steel, than cast iron', as hitherto moulded. And not only is thismetal rendered stronger-,z and its fibres made tocohere -with greater tenacity, by applying pressure, but another important result is= obtained,V which is, that in the act c'f applying pressure to condense tbe'metal, the latter is compelled to flow rapidly into every space in tliemould, thereby producing a perfectv casting atlevery operation. By subjecting cast ironto pressure while il: a molten sta'tc, the castings willbe homogeneous, because the metal in the mould will be subject to a uniform pressure throughout, which is not the case under the nld modes of casting east iron.

Iam aware that vsteel ear-wheels lhave been produced by subjecting this metal to pressure while in the monlds'in a liquider plastic state. An instance of' this kind will betonnd in the Letters Patent granted to me 'on the'30th day of July, "i867, and numbered 67,227, and therefore do not new lay claim broadly to a. eomprese'd metal car-wheel.

By my invention the'diculty and expense attending the construction of moulds adapted for moulding and condensing steel are greatly reduced, for the reason that the moulds do not require to be capable of withstanding so intense a lient when iron instead of steel is ren into them. Again, they do not require to be so strong as when steel is pressed within them.

Having described my invention- -I claim, as a new article of manufacture, a car-wheel made of cast iron, condensed by pressure while in s. molten state within the mould, substantially as and for the purpose described.

JOHN BLAKE TARR.

Witnesses:

IL T. CAMPBELL. Enw. Saunas. 

